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Extensive experimental and computational studies have demonstrated outstanding physical and chemical properties of the novel materials of compositionally complex carbides (CCCs), enabling their promising applications in advanced fission and fusion energy systems. This perspective provides a comprehensive overview of radiation damage behavior reported in the literature to understand the fundamental mechanisms related to the impact of multi-principal metal components on phase stability, irradiation-induced defect clusters, irradiation hardening, and thermal conductivity of compositionally complex carbides. Several future research directions are recommended to critically evaluate the feasibility of designing and developing new ceramic materials for extreme environments using the transformative "multi-principal component" concept. Compared to the existing materials for nuclear applications including stainless steels, nickel alloys, ZrC, SiC, and potentially high-entropy alloys, as well as certain other compositionally complex ceramic families. CCCs appear to be more resistant to amorphization, growth of irradiation defect clusters, and void swelling. [ABSTRACT FROM AUTHOR]

Reducing CO2 emissions is one of the major challenges facing the modern world. The overall goal is to limit global warming and prevent catastrophic climate change. One of the many methods for reducing carbon dioxide emissions involves capturing, utilizing, and storing it at the source. The Carbon Capture in Molten Salts (CCMS) technique is considered potentially attractive and promising, although it has so far only been tested at the laboratory scale. This study evaluates the wear of the main structural components of a prototype for CO2 capture in molten salts—a device designed and tested in the laboratories of AGH University of Kraków. The evaluation focused on a gas barbotage lance and a reactor chamber (made from Nickel 200 Alloy), which were in continuous, long-term (800 h) contact with molten salts CaCl2-CaF2-CaO-CaCO3 at temperatures of 700–940 °C in an atmosphere of N2-CO2. The research used light microscopy, SEM, X-ray, computed tomography (CT), and 3D scanning. The results indicate the greatest wear on the part of the lance submerged in the molten salts (3.9 mm/year). The most likely wear mechanism involves grain growth and intergranular corrosion. Nickel reactions with the aggressive salt environment and its components cannot be ruled out. Additionally, the applied research methods enabled the identification of material discontinuities in the reactor chamber (mainly in welded areas), pitting on its surface, and uneven wear in different zones. [ABSTRACT FROM AUTHOR]

Nickel significantly increases the toughness of steel and makes it ideal for use in applications that require high impact and fracture resistance at low temperatures. These inherent advantages position nickel steel as indispensable material in various domains, with a pronounced presence in stationary Liquefied Natural Gas (LNG) tanks and in the shipbuilding industry, particularly for tanks in vessels intended for the transport of liquefied ethane and LNG. The presented study focuses on assessing the fracture toughness behaviour of nickel alloy steel 1.5662+QT640 under sub-zero and cryogenic temperatures. The fracture performance of the material was evaluated, specifically emphasizing the impact toughness and fracture toughness characteristics of the material. Moreover, it was discussed if the transferability of the experimental results to the well-known fracture mechanics-based concept of EN 1993-1-10, which relies on the master curve concept, is possible. The results show that the master curve concept is not applicable to the nickel alloy steel 1.5662+QT640 due to its exceptional fracture toughness behaviour at very low temperatures. [ABSTRACT FROM AUTHOR]

This study explores the dissimilar welding of nickel superalloy 59 with Fe-Ni superalloy 904 L using the Gas Tungsten Arc Welding with Hot Wire technique (HW-GTAW). The HW-GTAW process produced defect-free weldments with complete penetration, as confirmed by macroscopic analysis. Microstructural analysis using FESEM and EDS revealed fine equiaxed and columnar dendrites in the fusion zone and identified a secondary phase enriched with chromium. XRD analysis supported the presence of predominant austenitic phases and indicated the formation of Cr23C6-type carbide. The grain size of the weld joint, determined using the Gaussian method and Scherer formula, was 44.53 nm, slightly smaller than base metals. Microhardness tests revealed values ranging from 226 ± 5 HV 10 to 243 ± 5 HV 10, with the highest values observed in the deep cryogenic treatment (DCT). The Mo in the ERNiCrMo-13 filler and the effects of DCT, which promote grain refinement, are responsible for this increase in hardness. Residual stress measurements revealed a maximum tensile stress of 315 MPa along the longitudinal axis and a maximum compressive stress of 355 MPa along the transverse axis. DCT enhanced the weldment's tensile strength by up to 12% compared to as-welded samples, with a 6% increase compared to shallow cryogenic-treated (SCT) samples. Charpy impact testing indicated a value of 88 J in the fusion zone, which is 1.2% less than alloy 59 and 9% higher than 904 L. Tensile fracture analysis revealed ductile dimples, while impact fractography showed a mix of ductile dimples and brittle, glassy cleavage facets. [ABSTRACT FROM AUTHOR]

The sluggish kinetics of alkaline hydrogen evolution reaction (HER) hinders practical exploitation of water splitting. Catalysts, known as platinum single atoms (Pt‐SAs) anchored in Ni4Mo/Ni alloys on nickel foam (Pt SAs‐Ni4Mo/Ni@NF) with ultralow Pt mass loading (mPt = 0.3 wt.%) derived from self‐reconstruction, with boosted atomic utilization in alkaline HER are demonstrated. In situ characterizations confirm the leaching of Mo species during the self‐reconstruction of NiMoO4, which facilitates the anchoring of Pt‐SAs through the generation of atomic defects. Further, density functional theory (DFT) calculations indicate that the atomic defects can effectively capture Pt2+ in salt solution, aiding in the distribution of Pt‐SAs. Besides, theoretical results emphasize that Pt SAs‐Ni4Mo/Ni with unique Pt‐Ni interaction can accelerate the desorption of hydroxides in alkaline electrolytes during HER, as well as lower energy barriers for reaction steps. Pt SAs‐Ni4Mo/Ni@NF shows remarkable catalytic activity toward alkaline HER with a low overpotential of 17 mV (j = 10 mA cm−2), together with high atomic utilization of Pt (8.92 A mgPt−1 at 30 mV) and excellent durability. This work not only provides a scalable preparation for efficient and robust low‐Pt catalysts but also establishes in‐depth understanding of the synergistic interaction between Pt SAs and Ni‐Mo alloys in alkaline HER, which is likely to accelerate the development of water‐splitting technique. [ABSTRACT FROM AUTHOR]

This study investigated the failure mechanism of the first-stage turbine rotor blades in a CT7 engine. Metallurgical analysis ruled out the possibility of failure due to the inherent properties of the blade material. A finite-element analysis (FEA) model for the blade was constructed based on computed tomography images. Thermomechanical FEA showed an increase in maximum principal stress on the failure region up to 17% when arch binding occurred. Moreover, a vibration mode analysis indicated that the natural frequency increased with the operational frequency. Based on a risk assessment considering the occurrence of failure, the risk index increased exponentially with the blade replacement interval. Thus, a replacement interval of 5600 engine flying hours is suggested to maintain the risk level within the safe threshold. [ABSTRACT FROM AUTHOR]

In this paper, the effectiveness of the eddy current methodology for crack detection in MAR 247 nickel-based superalloy with aluminide coatings subjected to cyclic loading was investigated. The specimens were subjected to force-controlled fatigue tests under zero mean level, constant stress amplitude from 300 MPa to 600 MPa and a frequency of 20 Hz. During the fatigue, a particular level of damage was introduced into the material leading to the formation of microcracks. Subsequently, a new design of probe with a pot core was developed to limit magnetic flux leakage and directed it towards the surface under examination. The suitability of the new methodology was further confirmed as the specimens containing defects were successfully identified. The changes in probe resistance values registered for damaged specimens ranged approximately from 8 to 14%. [ABSTRACT FROM AUTHOR]

VDM alloy (AM) 699 XA (AM-XA) produced by laser powder bed fusion (LPBF) was subjected to steam oxidation at different high temperatures. Initial studies on mass gain of AM-XA at 650 °C after 500 hours revealed insignificant changes. Typical to high temperatures, a wide range of oxides were obtained at 750 and 950 °C associated with mass gain. To fully understand AM-XA material behavior at high temperatures, hot-rolled 699 XA (HR-XA) was also fabricated and tested under similar conditions. At 750 °C, HR-XA showed a higher mass gain in comparison with AM-XA, whereas at 950 °C mass gain of AM-XA overtook HR-XA. This anomalous behavior was related mostly to carbide formation. In-depth anomalous behavior of AM-XA is explained by investigating the microstructure and phase composition of the oxidation products formed. [ABSTRACT FROM AUTHOR]

The vacuum carbon deoxidation process via CO formation has the ability to achieve high cleanliness of nickel alloys in vacuum induction melting. In the present study, the effect of vacuum degree in melting chamber, melt temperature, and initial carbon content on deoxidation efficiency was studied. The reactions of vacuum carbon deoxidization and MgO decomposition were strongly affected by chamber pressure and melt temperature. Low chamber pressure and high melt temperature resulted in a severe MgO-crucible decomposition reaction and increased oxygen supply to molten nickel alloy, and hence, decreased the deoxidation efficiency. Therefore, moderate vacuum degree in the chamber and lower melt temperature would improve the vacuum carbon deoxidation efficiency. The reaction rates of vacuum carbon deoxidization and MgO decomposition were controlled by the mass transfer of oxygen in liquid boundary layers near the reaction interfaces. The nitrogen in molten nickel alloy could be well removed together with carbon deoxidation under the vacuum conditions in the present study. A prediction model of deoxidation and carbon loss in vacuum melting process was established to determine the optimum temperature and vacuum conditions in vacuum carbon deoxidation process. [ABSTRACT FROM AUTHOR]

In recent years, the superalloys such as Inconel, Incoloy and Waspaloy are widely employed in aerospace, nuclear, automobile and marine applications due to their excellent properties. Besides, significant improvements in cutting tools and coatings have been done in recent years, which can be employed in machine superalloys for improving the machining performance. Their high temperature strength and toughness, quick work hardening, low thermal conductivity, tendency to weld onto cutting tools and ability to form built-up edges (BuE) make a challenge to machine nickel-based aerospace superalloys. The phenomena of BuE results in poor surface integrity and rapid tool wear. The selection of appropriate tool & coating material is based on type or grade of nickel alloy, its metallurgical condition and the machining operation to be performed. In this paper, a detailed review is presented to understand the current practices on advanced cutting tools and coating materials, coatings designs and effect of various tool coatings on machining performance. Further, the tool wear mechanism and machining performance under dry and other advanced sustainable environments such as MQL based vegetable oils, supercritical carbon-dioxide and hybrid nanofluids is presented in detail. [ABSTRACT FROM AUTHOR]

Black nickel coatings are pursued for both decorative purposes and advanced applications, including solar collectors, space technologies, and optical devices. The term "black nickel" typically refers not only to nickel but also to nickel alloys that can exhibit the characteristic black coloration, either bright or matte. This review provides an in-depth look at various techniques for producing black nickel coatings, focusing on both electrodeposition and electroless deposition methods. The discussion covers the different bath compositions and deposition conditions used to achieve the distinctive black color. The origins of black coloration in electrodeposited nickel and its alloys are shown in detail, emphasizing the crucial role of bath components and the formation of black compounds such as oxides, sulfides, and/or the nickel–zinc intermetallic compound. This review also highlights the necessity of oxidizing acid etching to blacken Ni–P electroless deposits, leading to the formation of a thin layer of black nickel oxides on a porous surface. The key properties of black nickel coatings are discussed, along with their relevance for various practical applications. [ABSTRACT FROM AUTHOR]

ABSTRACT The study investigated the effect of the oxidation–reduction cycles on the structure and corrosion resistance of the Haynes 282 nickel superalloy at ambient and elevated temperatures. The comparative studies were performed on specimens produced by the Powder Bed Fusion‐Laser Beam (PBF‐LB) process and those in the as‐received state. The microstructure of the PBF‐LB specimens was studied using optical and scanning electron microscopy, whereas the chemical composition of the scale formed after isothermal oxidation in an air atmosphere at 750°C was analysed using energy‐dispersive X‐ray spectroscopy and X‐ray Photoelectron Spectroscopy. The phase composition of the formed scale was determined by X‐ray diffraction. Laboratory‐induced hydrogen atmosphere was adopted through cathodic charging. A comparison of corrosion resistance was carried out on two types of Haynes 282 specimens, before and after the oxidation and cathodic charging processes. It was found that PBF‐LB process could be effectively used to manufacture Haynes 282 nickel superalloy with low porosity and a fine crystalline microstructure. The low‐porous, fine‐crystalline microstructure of the tested specimens produced by the PBF‐LB technique exhibited good resistance to electrochemical corrosion, slightly lower than wrought Haynes 282 nickel superalloy specimens. [ABSTRACT FROM AUTHOR]

Sliding electrical contacts are commonly applied in electrical connectors, such as conductive slip rings, pantographs, switches, and commutators. However, they suffer from several unavoidable problems caused by friction and wear, including high energy consumption, intermittent failures, limited life, and even failure disasters. In this study, we realized an ultralow-friction and long-distance wear-free state, defined as structural superlubricity (SSL), between sliding electrical interfaces under ambient conditions. A conductive SSL can be implemented in experiments with single-crystal graphite flakes on flattened metals, such as Au and Ni films. Furthermore, we found that depositing a 2 to 3-nm-thick diamond-like carbon (DLC) film on a nickel alloy can lead to an even lower resistivity than that of metals alone. In addition, we revealed the mechanism by which DLC films can improve the conductivity between graphite and metals through density functional-theory simulations. In addition, we prepared a prototype of the SSL slip ring and proved that it possessed ultralow friction, was wear-free, and had no intermittent failures. Consequently, our results demonstrate a unique type of electrical-contact interface for applications requiring conduction while sliding. Thus, we opened the door for SSL electromechanical coupling. [ABSTRACT FROM AUTHOR]

Electrooxidation of biomass‐derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value‐added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high‐efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu−NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu−NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm−2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII−OOH and CoIII−OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu−NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long‐term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass‐derived electrochemical refinery. [ABSTRACT FROM AUTHOR]

Features of high-temperature oxidation of N70VTYu-ID alloy with γ‑solid solution structure are studied. It is shown that characteristics describing this process stabilize with increasing oxidation time. The calculated oxidation activation energy is ~220,000 ± 5000 J/mol, which is comparable to the nickel self-diffusion activation energy. Influence of preliminary short-term high-temperature oxidation on alloy scale resistance is investigated. It is shown that this combined heat treatment can briefly increase N70VTYu-ID alloy scale resistance. [ABSTRACT FROM AUTHOR]

Rapid developments in aerospace and nuclear industries pushed forward the search for high-performance self-lubricating materials with low friction and wear characteristics under severe environment. In this paper, we investigated the influence of the Mo element on the tribological performance of nickel alloy matrix composites from room temperature to 800 °C under atmospheric conditions. The results demonstrated that composites exhibited excellent lubricating (with low friction coefficients of 0.19–0.37) and wear resistance properties (with low wear rates of 2.5–28.1 × 10−5 mm3/Nm), especially at a content of elemental Mo of 8 wt. % and 12 wt. %. The presence of soft metal Ag on the sliding surface as solid lubricant resulted in low friction and wear rate in a temperature range from 25 to 400 °C, while at elevated temperatures (600 and 800 °C), the effective lubricant contributed to the formation of a glazed layer rich in NiCr2O4, BaF2/CaF2, and Ag2MoO4. SEM, EDS, and the Raman spectrum indicated that abrasive and fatigue wear were the main wear mechanisms for the studied composites during sliding against the Si3N4 ceramic ball. The obtained results provide an insightful suggestion for future designing and fabricating solid lubricant composites with low friction and wear properties. [ABSTRACT FROM AUTHOR]

To reduce the cost of solution heat treatment process Ni-base single crystal superalloy TMS-238 containing Re and Ru, quantitative analysis of dendrite-interdendrite segregation of alloying elements under various solution heat treatment conditions were conducted, and influence on high-temperature creep strength were investigated. In this study, we defined the solution rate Rsol (= (1 − Vf,e) × 100%, where Vf,e is volume fraction of eutectic γ′ that precipitates in the final solidification zone during casting) as a parameter to reveal the microstructure homogeneity. The Rsol values were 71%, 97%, 99%, 100% for solutioning at 1250°C/20 h, 1320°C/5 h, 1320°C/20 h and 1335°C/20 h, respectively. Furthermore, it was confirmed that Re and W segregated in the dendrite core area and γ′ formers whereas Ta and Al segregated in the interdendrite. The magnitude of these segregations decreased as the solution temperature and time increased, and eventually the structure became almost homogeneous for solutioning at 1335°C for 20 hours. Additionally, creep test results indicate that Larson-Miller parameter (LMP) at 800°C–735 MPa, 900°C–392 MPa and 1000°C–245 MPa creep conditions show the same values for Rsol ≥ 97%. On the other hand, under 1100°C–137 MPa creep condition, LMP decreased as the Rsol decreased. A factor analysis of creep rupture properties suggested that the degradation of LMP under 1100°C–137 MPa was caused by the decrease of Re content and γ/γ′ lattice misfit in the interdendritic region. [ABSTRACT FROM AUTHOR]

Wire Electric Discharge Machining (WEDM) is an unconventional machining technology that uses electrical impulses to generate very high temperatures to cut material. The WEDM process hence causes some unfortunate defects, such as cracks and burnt cavities, which can impact the correct functionality of the machined pieces and shorten their service life. This study was carried out to understand which materials remain defect-free after WEDM. The examined materials were the Ampcoloy 35 copper alloy, the high-entropy steels FeCoCrMnNi and FeCoCrMnNiC0.2, and the B1914 and Nimonic 263 nickel alloys. The influence of the machining parameters, namely the pulse off time, gap voltage, discharge current, pulse on time, and wire feed, on the cutting speed and the surface topography of the machined piece was investigated. The surface morphology, the state of the subsurface layer in a cross-section, and the number of diffused elements from the wire electrode were analysed. All the analysed materials were found completely suitable for WEDM machining as they do not form any surface or subsurface defects. [ABSTRACT FROM AUTHOR]

Nickel based alloy was fabricated by a laser powder bed fusion using the blue laser with the wavelength of 450 nm and maximum output power of 200 W, and the effect of volumetric energy density (VED), on the porosity was evaluated for fabricated samples. A fabricated sample using the blue diode laser, recorded a porosity of 0.012% at the VED of 33 J/mm3, indicating that it can be fabricated more efficiently than the sample fabricated using the near-infrared fiber laser. Furthermore, it was revealed that when the surface roughness of the fabricated sample reached 37.5 μm, large voids were generated, indicating a high likelihood of void formation at a surface roughness of approximately 40 μm or more during the layer-by-layer fabrication of nickel-based alloys using the blue diode laser in powder bed fusion. [ABSTRACT FROM AUTHOR]

During high power laser welding of Inconel 740H, horizontal solidification cracks form at locations between approximately 70–80% of the weld depth. With the integration of circular beam oscillation, the laser energy density distribution and underlying thermo-mechanical conditions were altered. By coupling three-dimensional heat transfer, fluid flow, and stress modelling tools, the role that circular beam oscillation plays in the formation of the strain rates and stresses driving this cracking phenomenon was identified. While the addition of a circular oscillation pattern appeared to lower the stress levels along the solidification front, it did not eliminate the appearance of horizontal cracking. Only when the beam amplitudes reached 1.6 mm did solidification cracking disappear, but the weld depths were also significantly reduced. [ABSTRACT FROM AUTHOR]

In order to gain insight into the unique characteristics of manufacturing large-scale products with intricate geometries, experimental nozzle-shaped samples were created using wire-feed electron beam additive technology. Bimetal samples were fabricated from nickel-based alloy and copper. Two distinct approaches were employed, utilizing varying substrate thicknesses and differing fabrication parameters. The two approaches were the subject of analysis and comparison through the examination of the surface morphology of the samples using optical microscopy, scanning electron microscopy, and X-ray diffraction analysis. It has been demonstrated that the variation in heat flux distributions resulting from varying the substrate thicknesses gives rise to the development of disparate angles of grain boundary orientation relative to the substrate. Furthermore, it is demonstrated that suboptimal choice of the fabrication parameters results in large disparities in the crystallization times, both at the level of sample as a whole and within the same material volume. For example, for the sample manufacturing by Mode I, the macrostructure of the layers is distinguished by the presence of non-uniformity in their geometric dimensions and the presence of unmelted wire fragments. In order to characterize the experimental nozzle-shaped samples, microhardness was measured, uniaxial tensile tests were performed, and thermal diffusivity was determined. The microhardness profiles and the mechanical properties exhibit a higher degree of strength than those observed in pure copper samples and a lower degree of strength than those observed in Inconel 625 samples obtained through the same methodology. The thermal diffusivity values of the samples are sufficiently close to one another and align with the properties of the corresponding materials in their state after casting or rolling. The data discussed above indicate that Mode II yields the optimal mechanical properties of the sample due to the high cooling rate, which influences the structural and phase state of the resulting products. It was thus concluded that the experimental samples grown by Mode II on a thinner substrate exhibited the best formability. [ABSTRACT FROM AUTHOR]

Nickel alloys are widely used in aerospace and defense industries due to their excellent high-temperature characteristics. In order to increase fatigue resistance and oxidation corrosion resistance, aerospace curved surface parts always need to be strengthened using laser shock peening technology on five-axis machines. However, it is easy to generate dense laser spots in certain regions during the process, which might lead to an uneven distribution of residual stress on surfaces of the component. To address this issue, the study investigates the problem of excessive spot overlap rate at large curvature positions caused by a mismatch between the surface curvature of curved components and the dynamic performance of equipment, then proposes an optimization algorithm for motion control based on linear interpolation principles. By analyzing the relationship between the feed rate of the program segment and the actual feed rate, the speed of each axis of the machine tool is confirmed and adjusted, and the control flow of the optimization algorithm is established. The feasibility of the algorithm is preliminarily verified by comparing the changing trend of feed rate before and after optimization through simulation. In actual laser shock peening experiments on nickel alloy spherical shell elements, the laser spot distribution on the surface of the component is uniform, and the relative error range between the actual overlap ratio and the theoretical value can be controlled within 5%, demonstrating the correctness of the optimization algorithm. This study can significantly improve the surface machining quality of curved components and have practical applications. [ABSTRACT FROM AUTHOR]

Metal powder contributes to the environmental burdens of additive manufacturing (AM) substantially. Current life cycle assessments (LCAs) of metal powders present considerable variations of lifecycle environmental inventory due to process divergence, spatial heterogeneity, or temporal fluctuation. Most importantly, the amounts of LCA studies on metal powder are limited and primarily confined to partial material types. To this end, based on the data surveyed from a metal powder supplier, this study conducted an LCA of titanium and nickel alloy produced by electrode-inducted and vacuum-inducted melting gas atomization, respectively. Given that energy consumption dominates the environmental burden of powder production and is influenced by metal materials' physical properties, we proposed a Bayesian stochastic Kriging model to estimate the energy consumption during the gas atomization process. This model considered the inherent uncertainties of training data and adaptively updated the parameters of interest when new environmental data on gas atomization were available. With the predicted energy use information of specific powder, the corresponding lifecycle environmental impacts can be further autonomously estimated in conjunction with the other surveyed powder production stages. Results indicated the environmental impact of titanium alloy powder is slightly higher than that of nickel alloy powder and their lifecycle carbon emissions are around 20 kg CO2 equivalency. The proposed Bayesian stochastic Kriging model showed more accurate predictions of energy consumption compared with conventional Kriging and stochastic Kriging models. This study enables data imputation of energy consumption during gas atomization given the physical properties and producing technique of powder materials. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate the substitutional effect of typical A-side elements of Ce, Nd, Sm, and Gd on the crystal structure and hydrogen storage properties of an A 5 B 19 -type La 0. 72 Y 0. 13 Mg 0. 15 Ni 3. 70 Al 0.15 alloy aiming to provide further design for enhancing the commercial application of RE–Mg–Ni-based alloys for nickel-metal hydride (Ni/MH) batteries. The results reveal that Ce substitution significantly improves discharge ability at higher rates, delivering 283.3 mAh g−1 at 5C and 183.7 mAh g−1 at 10C, which present increases of 16.7% and 44.0% over the unsubstituted alloy, respectively. Additionally, Sm substitution effectively extends the alloy's cycling life, retaining 66.2% capacity after 500 cycles, representing a 14.4% increase compared to the original alloy. Moreover, the substitution of Nd increases the hydrogen storage capacity from 1.23 wt% to 1.50 wt%, while Gd reduces plateau hysteresis and slope factor during (de)hydrogenation. • Ce, Nd, Sm, and Gd substitution effects on A 5 B 19 -type alloy properties are revealed. • The high rate discharge ability of Ce-substituted alloy is elevated by 44.0% at 10C. • Nd substitution increases hydrogen storage capacity from 1.23 wt% to 1.50 wt%. • Sm substitution extends the 500th electrochemical cycling life from 14.4% to 66.2%. • Gd substitution reduces (de)hydrogenation plateau hysteresis and slope factor. [ABSTRACT FROM AUTHOR]

The use of ternary molten carbonate mixtures Li2CO3—K2CO3—Na2CO3 as heat transfer systems for the CSP technology as well as for heat storage for the chemical industry is widely under consideration. Experiments were carried out on austenitic steels DMV310N compared to nickel alloys in order to evaluate the corrosion properties in a molten 33 wt.% Li2CO3—33 wt.% K2CO3—34 wt.% Na2CO3 mixture at 700 and 750 °C for 1000 h in closed crucibles. The austenitic steel DMV 310N passivates by the formation of an outer LiFeO2 scale due to its iron content. If the iron content is low (< 5 wt.%), as in Alloy 625 the alloy forms NiO, which obviously does not passivate the material and leads to a strong internal corrosive attack. It has been shown by short-term experiments (3, 30, 300 and 1000 h) that a quick formation of LiFeO2 is necessary to avoid chromium dissolution and NiO formation. If LiFeO2 is formed quickly, the growth of the internal corrosion front by chromium dissolution is retarded. [ABSTRACT FROM AUTHOR]

Structural materials in fast reactors with harsh radiation environments due to high energy neutrons—compared to thermal reactors—potentially suffer from a higher degree of radiation damage. This radiation damage can change the thermophysical and mechanical properties of materials and, as a result, alter their performance and effective lifetime, in some cases leading to their disintegration. These phenomena can jeopardize the safety of fast reactors and thus need to be investigated. In this study, the effect of radiation damage on the vessels of molten salt fast reactors (MSFR) was evaluated based on two fundamental radiation damage parameters: displacement per atom (dpa) and primary knock-on atom (pka). Following the previous part of this article (Parts 1 and 2), an iMAGINE reactor core design (University of Liverpool, UK—chloride-based salt fuel system) and an EVOL reactor core design (CNRS, Grenoble, France, fluoride-based salt fuel system) with stainless steel and nickel-based alloy material vessels, respectively, were considered as case studies. The SPECTER and SPECTRA-PKA codes and a PTRAC card of MCNPX, integrated with a module which has been developed in MATLAB, named PTRIM and SRIM-2013 (using binary collision approximation), were employed individually to calculate and compare dpa and PKA (this master module containing all three tools has been appended to the iMAGINE-3BIC package for future use during reactor operations). Additionally, SRIM-2013 was applied in a 3D simulation of a radiation damage map on a small sample of vessels based on the calculated PKA. Our results showed a higher degree of radiation damage in the iMAGINE vessel compared to the EVOL one, which could be expected due to the harder neutron flux spectrum of the iMAGINE core compared to EVOL. In addition, the nickel alloy vessel showed better radiation damage resistance against high energy neutrons compared to the stainless steel one, although more investigations are required on thermal neutrons and alloy corrosion mechanisms to determine the best material for use in MSFR vessels. [ABSTRACT FROM AUTHOR]

This article discusses the evaluation of tool wear during the turning of Inconel 718 using self-propelled rotary tools (SPRTs) and conventional round tools (CRTs). The study aims to understand the tool wear progression and develop mathematical models to analyze the effect of cutting parameters and machining time on tool wear. The researchers conducted experiments with different cutting conditions and measured tool wear using scanning electron microscopy and digital microscopy. The results show that SPRTs have longer tool life and more uniform wear compared to CRTs. The article provides valuable information for the metalworking industry to make decisions about tool replacement and cutting conditions. [Extracted from the article]

Surface grinding is a widely employed finishing process in industrial sectors dedicated to achieve desired Surface characteristics of components. This study experimentally investigates the impact of the grinding parameters pertaining to the surface characteristics of Inconel 800, which is a nickel-iron-chromium alloy extensively used in high-temperature applications. Various commercially available grinding wheels were employed to grind Inconel800 under different grinding conditions. The ground surfaces were comprehensively analyzed using surface roughness measurements, Three-dimensional profilometry, optical microscopy, findings from XRD and SEM reveal that grinding parameters and wheel characteristics significantly impact the surface texture, topographical features, residual stress, and surface morphology of the machined nickel alloy.. The insights from this investigation contribute to the understanding of the grinding behavior of nickel-based superalloys and provide a basis for optimizing the grinding process for enhanced surface integrity. The findings are valuable for industries dealing with the machining of high-performance nickel alloy components. [ABSTRACT FROM AUTHOR]

Alloy 625 plays a crucial role in high-pressure hydrogen environments typical of hydrogen refuelling stations, where cyclic temperature and loading conditions prevail. In this study, we reveal that hydrogen-induced ductility loss of nickel-based alloy 625 significant difference which change from 11.9% at slow strain rate to 20.1% at conventional strain rate. The difference can be attributed to a change in deformation mode: from dislocation slipping under slow strain rate to twinning under conventional strain rate. Specifically, hydrogen-refined deformation twins and the promotion of twin bundles under conventional strain rates diminish the twin-induced plasticity effect of the alloy. This shift in deformation mode also alters the hydrogen embrittlement mechanism across the two strain rates. These findings provide valuable insights for hydrogen embrittlement-resistant designing and evaluating hydrogen compatibility for alloy 625. [Display omitted] • The nickel-based alloy 625 has more significant hydrogen-induced ductility loss at 5 × 10−3 s−1 than that at 5 × 10−6 s−1. • The deformation mode change from dislocation slipping at 5 × 10−6 s−1 to twinning at 5 × 10−3 s−1. • Hydrogen weakens the TWIP effect of the alloy because of hydrogen refining DTs. • Hydrogen will promote the formation of deformation twin bundles, resulting in cracking along DTs. • A new mechanism of hydrogen-induced cracking along DTs in nickel-based alloys was proposed. [ABSTRACT FROM AUTHOR]

Laser beam welding is the most modern and promising process for the automatic or robotized welding of structures of the highest Execution Class, EXC3-4, which are made of a variety of weldable structural materials, mainly steel, titanium, and nickel alloys, but also a limited range of aluminum, magnesium, and copper alloys, reactive materials, and even thermoplastics. This paper presents a systematic review and analysis of the author's research results, research articles, industrial catalogs, technical notes, etc., regarding laser beam welding (LBW) and laser hybrid welding (LHW) processes. Examples of industrial applications of the melt-in-mode and keyhole-mode laser welding techniques for low-alloy and high-alloy steel joints are analyzed. The influence of basic LBW and LHW parameters on the quality of welded joints proves that the laser beam power, welding speed, and Gas Metal Arc (GMA) welding current firmly decide the quality of welded joints. A brief review of the artificial intelligence (AI)-supported online quality-monitoring systems for LBW and LHW processes indicates the decisive influence on the quality control of welded joints. [ABSTRACT FROM AUTHOR]

Due to its super plasticity, low weight, and high mechanical resistance properties, generally, Ti6Al4V is used for aeronautical applications. However, it has low resistance to plastic shearing. In addition, it has poor wear resistance. For these reasons, a lot of techniques have been developed to improve its wear resistance. Investigations of microstructure and interfacial reactions of diffusion bonding of Ni and Ti6Al4V materials have been performed experimentally. Ni samples were prepared with 50 ± 5 µm Ni powders in cylindrical shape. For diffusion bonding, Ag foil was used for improving the interlayer and connection quality. Nickel and its alloys can be joined by using some different processes, and the use of an interlayer can further facilitate the joining process and improve the joint quality. The experiments were carried out under the protected atmosphere. Argon gas was used for protection. The experiments were performed under 5 MPa pressure for 60 min duration at 850 °C, 900 °C, and 950 °C thermal conditions. Investigations of metallurgical structure occurring in the interface areas were examined by optic analysis of EDS, SEM, and X-ray. The strength of the joints was tested by lap-shear tests. From observations, the best quality of the coalescence at interfaces was indicated at elevated temperatures. [ABSTRACT FROM AUTHOR]

The relation between the ultimate strength σb and contraction ψ vs stress concentration factor Kt of smooth and notched cylindrical specimens from cast and aging austenitic-martensitic steels, solution-hardened austenitic steel, and powder and deformable dispersion-hardened nickel alloys was studied at pressures of gaseous hydrogen up to 35 MPa and temperatures up to 1073 K. At room temperature, the effect of hydrogen on σb and ψ of all materials was revealed at 1 MPa; it is enhanced with the pressure up to 20 MPa and Kt from 1 to 4.602 in V-notch specimens with maximum and minimum diameters of 7 and 5 mm, respectively, and radii at the notch root of 0.1 and 0.2 mm, a further increase in the hydrogen pressure to 35 MPa does not bring about additional deterioration of material properties. The hydrogen embrittlement of an EK-62 heat-resistant nickel alloy does not almost depend on the stress concentrations. The effect of hydrogen decreases with temperature but remains essential in the range of 293–723 K (VNL-6 steel), 293–973 K (EP-901 alloy), and 293–1073 K (EK-62 alloy). The most sensitive to hydrogen are VNL-6 cast austenitic coarse-acicular martensitic steel and an EK-62 alloy with a great amount of intermetallics wherein, unlike other materials, the embrittlement appears not only as a noticeable decrease in ductility but also in ultimate strength of both smooth and notched specimens. The strengths of hardened specimens from ChS-37 steel, EP-666 alloy, and VZhL-14P aged alloy are not affected in the hydrogen atmosphere, and contraction is relatively small. A VZhL-14 powder metallurgical fine-dispersed alloy with almost the same ultimate strength is the least sensitive to hydrogen embrittlement among heat-resistant dispersion-hardened nickel-base alloys. [ABSTRACT FROM AUTHOR]

The results of structural studies and assessment of the bending strength of a VKNA-4U alloy based on nickel aluminide are presented. It is for the first time that this alloy was produced by spark plasma sintering of mechanically activated powders of the starting components. The mechanical activation of the powders lasted for 1.5, 3.5, and 5 min. X‑ray diffraction analysis was performed to determine the optimal duration (3 min 30 sec) of mechanical activation for this alloy. To obtain a dense low-defect workpiece, the VKNA-4U alloy was sintered at a heating temperature of 1100 °C, a pressure of 40 MPa, and a holding time of 5 min. This material has higher ultimate bending strength at room temperature (σbend = 1215 ± 65 MPa) than the strength of Ni3Al intermetallic compound produced in similar conditions and microhardness 690 ± 25 HV. [ABSTRACT FROM AUTHOR]

Heat-resistant nickel alloys are promising materials for manufacturing structural elements used in high-temperature nuclear power plants. Nickel alloys are characterized as difficult-to-weld materials; this is one of the main factors limiting their use. This paper presents the results of the development and industrial exploitation of welding technology for heat-resistant nickel alloy grade CrNi62MoCh2-VI (EC 199-VI). The quality control results of the obtained welded joints are presented. Notably, the welded joints of the CrNi62MoCh2-VI alloy exhibit resistance to intercrystalline corrosion and demonstrate improved mechanical characteristics. [ABSTRACT FROM AUTHOR]

In this paper, an isothermal diagram of the second phase formation in the Hastelloy G35 alloy was constructed to understand possible phase transformations during welding. A welded joint has been studied in three areas: fusion zone (FZ), the heat affected zone (HAZ), and the base metal (BM). The FZ is represented by a dendritic structure; in addition, σ-phase intermetallic compounds are present in the FZ and HAZ. Furthermore, the FZ and BM present similar hardness values, while the hardness increases in the HAZ. It has been established that thermal effects for different areas are characterized by different rates of increase up to 650°C. [ABSTRACT FROM AUTHOR]

Corrosion-resistant nickel-based alloys are of interest because of their potential applications in various industries, where the operations involve aggressive environments, including high temperature conditions. The results of measuring the modulus of elasticity under isothermal exposure of various durations in the temperature range of 350–650°C are presented. It is shown that two simultaneous processes are observed in the alloy under study: the formation of an ordered phase and the austenite lattice compression. [ABSTRACT FROM AUTHOR]

This paper investigates a new type of metal matrix composite, namely elemental metal matrix composites (EMMC), where a matrix contains elemental metal powders joined at selective interfaces with other property-enhancing powders to strategically preserve properties of individual constituents. These composites have the potential advantage of reduced demands on high-temperature processing while boasting unique multifunctional properties. cBN-reinforced nickel alloy 20/Cu80 composites (with cBN content ranging from 0 to 5 wt.%) were fabricated using a powder metallurgy processing sequence. The saturation magnetization, the coercivity, electrical resistivity, thermal conductivity, and hardness of the EMMCs were investigated. An increase in cBN content from 1 to 5 wt.% resulted in a slight decline in the relative green and sintered density by about 5% and thermal conductivity from 155.95 to 59.16 W/(m.K) while increasing the electrical resistivity from 4.59 to 12.10 µΩ cm, saturation magnetization from 9.51 to 11.94 emu/g, and hardness from 164 to 206 HV. However, the coercivity decreased from 4 to 2.7 Oe. In accordance with the rule of mixtures and the Maxwell model, an increase in thermal conductivity with an increase in cBN content is predicted. However, using Wiedemann–Franz law (using experimental electrical resistivity measurements) shows a decline in thermal conductivity with increase in cBN content, due to multiple factors related to the sintered EMMCS including porosity, cBN agglomeration, and reduced interfacial bonding between powder constituents. [ABSTRACT FROM AUTHOR]

The aim of this work was to verify the possibility of forming Ni-Fe and Co-Fe alloys via topotactic ion exchange exsolution in Fe-infiltrated (La,Sr,Ce)0.9(Ni,Ti)O3-δ or (La,Sr,Ce)0.9(Co,Ti)O3-δ ceramics. For this purpose, samples were synthesized using the Pechini method and then infiltrated with an iron nitrate solution. The reduction process in dry H2 forced the topotactic ion exchange exsolution, leading to the formation of additional round-shape structures on the surfaces of grains. EDS scans and XRD analysis confirmed the formation of bimetallic alloys, which suggests that these materials have great potential for further use as anode materials for Solid Oxide Fuel Cells (SOFCs). [ABSTRACT FROM AUTHOR]

The paper presents the results of testing the wear resistance and coefficient of friction (COF) tools made of SikaBeresin® F50 polyurethane resin intended for dies and punches for the cold sheet metal forming process. Seven sets of composite tools (rotating rings) additionally reinforced with waste metallic powders from Al and Cu alloys (5-20% by volume) from the dry cutting process of pipes and rods were tested. Wear resistance tests and determination coefficient of friction were carried out using the T-05 block-on-ring tribotester. The tests were performed for heat and corrosion resistant sheets made of nickel alloy AMS5599 (Inconel 625), iron alloy AMS5510 (321) and aluminum alloy sheets AMS4026 (6061-T4). Composite tools with the addition of 20% aluminum powder (A+B+C+20%Al) tested with a specimen of steel alloy AMS5510 and nickel alloy AMS5599 were characterized by the lowest wear resistance. In each case, the composite rotating ring without reinforcements was characterized by the lowest coefficient of friction. The use of Cu powder reinforcements in each case had a positive effect on increasing wear resistance. The best wear resistance of 0.011% was obtained for composite rotating ring with the addition of 10% copper powder paired with specimen of nickel alloy AMS5599 sheet. [ABSTRACT FROM AUTHOR]

The study provides a qualitative assessment of the maximum rate of metal powder processing, which ensures obtaining a high density product by selective laser melting. The maximum rate is determined by the characteristic times of the main physical processes for the formation of a solid material in the course of selective laser melting: heating, warming, melting, and spreading. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate the influence of nickel alloy type from the same group, the parameters of flame spraying, as well as the preparation of the substrate and the heat treatments of the substrate on the microstructure of the coating/substrate system. Due to the possibility of applying nickel alloys in corrective maintenance of tools used on elevated working temperatures, hot work tool steel X38CrMoV5-1 was selected as a substrate material. The investigation of the microstructure of the coating/substrate system was carried out according to the factorial design of experiment, where the input factors were varied on two levels. The factors that were varied are: Ni-based self-fluxing alloys - NiCrBSi and NiBSi; distance of the burner from the workpiece - small (6 mm) and large (20 mm); preparation of the substrate - roughened and non-roughened and the heat treatments of the substrate - soft annealed and tempered condition. Ni-based self-fluxing alloys were applied on samples (12,5 × 25 × 25 mm) by flame spraying with simultaneous fusing process. Analysis of the microstructures of the coating/substrate system was carried out on the Leica DM 2500M light microscope. After the conducted analysis the paper concluded that by spraying the selected coatings onto the X38CrMoV5-1 tool steel base, poor quality coatings are obtained, due to the appearance of cracks (NiCrBSi) or separation of the coating from the substrate (NiBSi). This is attributed to the formation of martensitic structure of the substrate after spraying and the presence of residual stresses. [ABSTRACT FROM AUTHOR]

This study was intended to investigate the mechanical property at high temperature and cutting performance of cemented carbide for machining of exotic materials, such as nickel alloys, cobalt alloys, and titanium alloys. Exotic materials are widely used for equipment and parts in the aerospace and automotive industries due to their superior heat and corrosion resistance. When machining exotic materials, its low thermal conductivity causes the cutting edge temperature to be higher than when cutting steel, and the hardness of the tool material decreases, resulting in extremely low tool life. However, because cemented carbide in particular contains metals in its composition, plastic deformation of the cemented carbide cannot be prevented even when the coating has sufficient heat resistance. The WC-Co-NiCr alloy, in which NiCr partially replaces Co as the binder phase of cemented carbide, has improved high-temperature properties while maintaining room temperature properties compared with conventional WC-Co alloys, and tool life has been improved in machining exotic alloys. [ABSTRACT FROM AUTHOR]

Isothermal compressive experiments on a Ni-based superalloy were performed at strain rates from 0.001 to 1 s-1 and temperatures between 920 and 1040 to study its high--temperature deformation. Utilizing the experimental data, a Long Short-Term Memory (LSTM) model, optimized with the Particle Swarm Optimization (PSO) algorithm (LSTM--PSO), was developed to characterize this behavior. The LSTM component of the model effectively handles the complexity and nonlinear characteristics of time-series data, while the PSO component performs parameter optimization, enhancing the model's accuracy and generalization capability. The model's inputs include deformation temperature, strain rate, and true strain, with true stress as the output. A comparison of experimental and forecasted results revealed that the LSTM-PSO model accurately predicts high-temperature deformation, achieving a correction coefficient of 0.9988 and an average absolute relative error of 1.16, demonstrating superior performance compared to other advanced methods. [ABSTRACT FROM AUTHOR]

The creep mechanism of a Co-based single-crystal (SX) superalloy at 760°C/800 MPa (∼90% yield strength) was revealed and differed from those of Re-containing Ni-based SX superalloys. Experimental alloy displays superior creep resistance in the early creep stage, likely due to the accumulation of matrix dislocations and W segregation-assisted shearing of γ′ phase by leading Shockley partial dislocations instead of Co and Cr segregation a < 112> SF ribbons in Re-containing Ni-based SX superalloys during the accelerating creep stage. Segregation-assisted local χ/η phase transformations at SFs stabilize and enhance SF interactions, contributing to the subsequent slow accelerating creep stage. [ABSTRACT FROM AUTHOR]

In a two-step reduction process, Ni-based alloy nanocatalysts (Ni-ANCs) made of nickel-iron-cobalt with a carbon support (Ni–Fe–Co/C) were produced in various molar proportions. A comprehensive structural characterization of the morphology and composition of Ni-ANCs was evaluated using XRD, TEM and EDX analyses. The XRD results from Ni-ANCs indicated a diffraction pattern that was caused by only one face-centered cubic (FCC) phase, indicating that the ternary metals Instead of a phase-separated structure, a well-mixed solid solution structure was created. TEM images showed that Ni-ANCs have a particle size of between 13 and 30 nm uniform dispersivity on the carbon support. At the same time, the electrochemical activities of Ni-ANCs were evaluated by means of CV, LSV and CA investigate for the Induction of electrooxidation in ethylene glycol at room temperature. Experimental results reveal that Ni 60 Co 40 /C and Ni 60 Fe 30 Co 10 /C are substantially more potent than Ni 60 Fe 40 /C and Ni 100 /C respectively, when using Co-containing alloy nanocatalysts. Specifically, the ternary Ni 60 Fe 30 Co 10 /C catalyst has a higher electrochemical activity than its binary counterpart, which can be attributed to the conductivity and deformation effects. This is noteworthy because it demonstrates that Co accelerates the oxidation of Ni to a more active NiOOH at a lower overpotential level, enabling otherwise inactive Fe sites within the Ni (OH) 2 phase to become active. A Micro flow channel with distinct zones and its structure and cross-section for the MLEGFC [Display omitted] • The structural characterization of the morphology and composition of Ni-ANCs was evaluated using XRD, TEM and EDX analyses. • TEM images showed that Ni-ANCs have a particle size of between 13 and 30 nm. • A greater activity of Ni 60 Fe 30 Co 10 /C can be observed than Ni 60 Co 40 /C and Ni 60 Fe 40 /C, however, Ni 100 /C is lower. [ABSTRACT FROM AUTHOR]